A conventional socket for driving bolt head or nut generally includes a tubular body with a receiving recess at one end of the tubular body so as to be connected with a ratchet tool and an engaging recess is defined in the other end of the tubular body such that a bolt head or a nut can be mounted by the engaging recess and driven. There are so many shapes for the bolt head or the nut, such as hexagonal head which can be seen in most of the bolts, square head, star-shaped bolt head, or toothed bolt head which is only driven by special tool. Furthermore, metric sized and English sized bolt heads are slightly different so that the users need to prepare two different size systems of tools to successfully drive these bolt heads. Using a metric-sized socket to drive an English sized bolt head could damage the peaks of the bolt head or the peaks are not well positioned in the engaging recess so that when rotating the socket, the bolt head is driven at only a limited angle, and this is not efficient.
The present invention intends to provide a socket that includes 24 or 36 points and an opening between two adjacent points is smaller than a width between the root portions of the two adjacent points. By this arrangement, the socket may successfully drive any type of bolt head or nut.